892006 2:453:30pm

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• 8/9/2006 245-330pm
• Integrating WiFi Telephony Into the Enterprise
  Communications Infrastructure Organizations are
  become increasingly aware of the benefits VoIP
  provides as a collaborative communication tool.
  Those businesses that demand communicative
  flexibility and efficiency are now beginning to
  examine new wireless technologies to help meet
  these needs. The introduction of new wireless
  VoIP solutions can now offer the type of vital
  integration and convergence of multiple
  communication tools that todays mobile business
  must have to be successful. This session will
  cover the development of wireless VoIP solutions,
  as well as the issues you need to consider before
  implementing a wireless communication solution
  including network assessment, varying approaches
  to wireless design, securing your wireless
  network and the potential return on a wireless
  investment.
• This will be a shared session with Spectralink. 
  NEC will speak first from 245-305 and
  Spectralink will follow from 305-325, with a 5
  minute QA at the end.

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Tom Grady Product Manager NEC Unified Solutions
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Integrating WiFi Telephony Into the Enterprise
Communications Infrastructure
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Voice User Requirements

• Coverage and Bandwidth specific to voice traffic
• Site survey for voice different than for data
  (higher BW requires higher signal strength)
• IP assessment on wired network for VoIP support
  may be needed
• Security
• Network security more intrusive to voice latency
  and jitter concerns
• Encryption and authentication add CPU latency to
  voice stream
• Quality of Service
• Delay and jitter negatively impact voice as
  opposed to data
• Must give priority to voice traffic over data
• Admission control important in dense user
  environment
• Mobility
• Voice traffic on wireless network introduce new
  layers of service requirements above data traffic
  requirements

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Network requirements for voice

• Must Consider
• Latency- the time it takes to get information
  through a network
• Jitter- if a network provides various latency for
  different packets, it introduces jitter
• Packet Loss- packets lost due to collisions or
  retransmissions
• AP Handoff- the time it takes a device to
  re-associate and re-authenticate at Layer 2
• Wireless Network Requirements for Voice
• Maximum jitter lt 5 msec
• Maximum latency lt 50 msec
• Maximum Packet Loss lt 1
• AP handoff lt 50 msec

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Wireless Voice Considerations

• No time for retransmission of lost or corrupted
  packets
• Real-time, full duplex voice conversations
  require voice packets to received within tens of
  milliseconds
• Users are extremely very mobile
• Frequent handoffs
• Real-time application
• Coverage issues are audible
• Poor voice quality creates the perception of
  substandard product
• Cover all user-accessible areas
• Stairwells, bathrooms, break rooms and lobby
  areas must have coverage

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Remember
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Voice has Different Requirements

• Signal Strength smaller number is better
  (stronger signal)
• Data WLAN -85dBm
• Voice WLAN -65 to -70dBm with 15 - 25 cell
  overlap
• Signal-to Noise Ratio higher is better
• Data WLAN 15dB
• Voice WLAN 20dB minimum for good quality voice
  calls
• Interference
• Eliminate overlapping channel interference with
  proper channel assignments
• Data Rate depends on radio type a/b/g
• Will be affected by network load

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Power and Range
Voice Traffic
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Design Approaches

• Consider
• Number of potential concurrent clients
• Voice clients
• Available vs. concurrent
• Consider second or third overlappingaccess point
• Consider output power constraints
• Reduce cell size, hence number of concurrent
  clients

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Why do a Wireless Site Survey?

• To accurately determine
• The number and placement of access points (APs)
  needed for required coverage and throughput.
• Where blind spots are, so you can avoid them.
• Are there any unauthorized APs (rogues) already
  connected to your network?
• Is there any RF interference present?

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The Final Solution
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To recap

• A wireless site survey accurately determines
• The number of access points (APs) needed for
  adequate coverage.
• The placement of access points (APs) for
  coverage and throughput.
• Where blind spots are, so you can avoid them.
• Are there any rogues already connected to the
  network?
• Is there any RF interference present?
• Are there other 802.11 networks in the vicinity?

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QoS Considerations for High Quality Voice

• Admission Control is required
• Streaming applications need priority service
• Bandwidth management required to maximize
  capacity and minimize contention
• Battery life must be maximized
• Traffic is predictable
• Schedule periods of sleep are possible
• VoIP Bandwidth Control
• Dynamic QoS
• Fast Handoff

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VoWLAN Mobility Fast Roaming

• Wireless voice users must be free to roam
• Fast roaming requires sub 150ms handoffs ideally
  lt50ms
• No dropped calls due to roaming across layer 2 AP
• No dropped calls due to subnet roaming
• Must be able to support security options within
  fast roaming constraints

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Security Considerations for Voice

• Security threats
• Intercepting telephone calls is expensive
  relative to the value of the information
• Access to corporate network is the primary issue
• Usability
• No established paradigm for logging in to a
  telephone
• Minimize handoff duration
• Clients are highly mobile
• Packets have a limited useful life
• Streaming application have low delay tolerance
• Application specific devices
• Handsets do not necessarily use standard PC
  operating systems
• Handheld devices may have limited processing
  power, memory constraints, and battery life issues

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Security Components

• Information access protection
• Encryption algorithm scrambles data into
  unintelligible information using a key
• Data is unencrypted using the same key at the
  receiving end
• Key management
• Process for providing keys at each end of the
  secured link
• Provides mechanism for changing keys at
  appropriate intervals
• Authentication
• Mechanism to verify identity of users
• Prevents man in the middle attack
• Message integrity
• Verifies that the information current
• Prevents replay or cut and paste attacks

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Wi-Fi Protected Access (WPA)

• Defined by the Wi-Fi Alliance
• Mandatory for Wi-Fi certification
• Based on IEEE 802.11i
• Intended to be software/firmware upgrade from WEP
  for legacy wireless devices
• Key elements
• 802.1x authentication
• Extensible Authentication Protocol Transport
  Layer Security (EAP-TLS) for authentication
  management systems
• Pre-Shared Key (PSK) for real-time applications
• Encryption and key rotation
• Temporal Key Integrity Protocol (TKIP)
• RC-4 encryption algorithm
• Validation
• Michael message integrity check (MIC)

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Security Ramifications for Voice

• Handoff authentication delay must be addressed
  for enterprise applications
• Pre-shared key (WPA/WPAII)
• Usability issues
• Simple user login process
• Device design
• Additional processing power and memory
  requirements

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Value Proposition

• To build a solution platform that enables
  converged mobility to penetrate multiple
  verticals and unifies voice, multimedia and data
  in the wireless workspace while enabling robust
  mission-critical business applications and
  solutions

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Converged Mobility ROI in HealthCare
2003
2006
Source Office of Medicare and Medicaid Financing